The present invention relates generally to semiconductor packaging, and more particularly to a lead frame for packaging semiconductor devices that reduces the detrimental effects of burr formation during the singulation process.
Conventional semiconductor package devices 10, such as single row lead frame design quad flat no-lead (QFN) packages as shown in FIGS. 1A-1B, typically are assembled using matrix array packaging (MAP). MAP type semiconductor package devices are processed and manufactured as multiple semiconductor package devices on a single substrate bar unit. During assembly, the single substrate bar unit is divided into individual and discrete semiconductor package devices by a singulation process.
Each semiconductor package device 10 typically includes a lead frame with leads 12 and die bond area 14. A semiconductor integrated circuit (IC) die (not shown in FIGS. 1A-1B) is fixed or bonded to the die bond area 14 of the lead frame with adhesive such as an epoxy material. The lead frame is the central supporting structure of the semiconductor package device. After the IC die has been attached to the die bond area 14, the IC die is electrically connected to the leads 12 with wires by a wire bonding process to enable electrical interconnection between the IC die and an underlying substrate such as a printed circuit board (PCB). A mold compound 16 of ceramic or plastic material then encapsulates or partially encapsulates the die, wires, and part of the lead frame to protect them from the environment. Singulation is then performed on the encapsulated assemblies of the MAP to separate and complete the process of making discrete semiconductor package devices 10.
Conventionally, there are two types of singulation processes, saw singulation and punch singulation. During the singulation process of MAP devices, the semiconductor package device may become damaged as shown with a device 20 in FIG. 1B. For example, in saw singulation, formation of burrs 22, caused by the saw 24 smearing the leads 12 in the saw path direction 26, can cause one lead to extend to an adjacent lead. The burr 22 can lead to device failure as the smeared material may cause shorting between adjacent leads. Burr formation is becoming a greater concern in the industry as the number or density of input/outputs (IO) is increasing and the pitch or distance 28 between adjacent leads is becoming smaller. That is, there is a growing risk of burr formation and shorting.
Accordingly, there is a need to address or at least alleviate the above problems associated with conventional semiconductor package devices to reduce the detrimental effects of burr formation during singulation.